The tail of the AirAsia plane that crashed into the Java Sea has been spotted, but an Indonesian official says the tail is upside down and partially buried – with the assumption that the plane’s black boxes could be buried in mud.

Suryadi B. Supriyadi, the director of operations at Indonesia's National Search and Rescue Agency, said equipment such as a crane or floating balloon are being prepared to lift the objects. That process has not yet begun, he said.

The black boxes – which are located in the plane’s tail section – may offer essential information about the doomed flight, including recordings of cockpit voice and flight data.

BASARNAS handout

An underwater photo released by Indonesia's National Search And Rescue Agency (BASARNAS) on Jan. 7, 2015 shows wreckage from AirAsia Flight 8501 in the Java Sea.

Authorities released underwater images Wednesday showing the wreckage. Bambang Soelistyo, the head of Indonesia's National Search and Rescue Agency, said the letters “A” and “X” were visible, along with the stylized dot in AsiaAir’s logo, matching the plane's tail.

“My conclusion is today, we had success in obtaining a part of the plane which became a key target since yesterday and today,” he said.

The tail was located about 19 miles away from the primary focus area, authorities said.

"We would like to extend our appreciation to all authorities and personnel that has been involved in the [search and rescue] operation," he said in a statement.

BASARNAS handout

An underwater photo released by Indonesia's National Search And Rescue Agency (BASARNAS) on Jan. 7, 2015 shows wreckage from AirAsia Flight 8501 in the Java Sea.

Soelistyo said the top priority remains recovering more bodies. An additional body was recovered Wednesday, Soelistyo said, the 40th body recovered in the tragedy.

The plane was carrying 162 people when it crashed Dec. 28. The water at the crash site is shallow, but this is the worst time of the year for a recovery operation to take place due to seasonal rains that have created choppy seas and blinding mud and silt from river runoff.